[U-Boot] [PATCH] cmd_pci: Check for VendorID earlier

[Fabio Estevam]

Hi Simon,

On Fri, Oct 9, 2015 at 10:01 AM, Simon Glass <sjg at chromium.org> wrote:

> I'm just surprised that it is failing when there is nothing there. I
> think it should succeed (and read 0xffff).
>
> What board is this? Can you find the code that is returning this
> error? It may be a call to pci_set_ops() which sets read_word().

It is a mx6qsabresd board.

I don't have the PCI device at the moment to give it a try, but
looking at the code, in pcie_imx we have:

    pci_set_ops(hose,
            pci_hose_read_config_byte_via_dword,
            pci_hose_read_config_word_via_dword,
            imx_pcie_read_config,
            pci_hose_write_config_byte_via_dword,
            pci_hose_write_config_word_via_dword,
            imx_pcie_write_config);

Then in drivers/pci/pci.c:

#define PCI_READ_VIA_DWORD_OP(size, type, off_mask)            \
int pci_hose_read_config_##size##_via_dword(struct pci_controller *hose,\
                    pci_dev_t dev,            \
                    int offset, type val)        \
{                                    \
    u32 val32;                            \
                                    \
    if (pci_hose_read_config_dword(hose, dev, offset & 0xfc, &val32) < 0) {    \
        *val = -1;                        \
        return -1;                        \
    }                                \
                                    \
    *val = (val32 >> ((offset & (int)off_mask) * 8));        \
                                    \
    return 0;                            \
}

,which returns -1 (and also *val = -1) in the case of errror, which
matches the values that I was reading yesterday

Regards,

Fabio Estevam